Heat recoverable article and process



July 15, 1969 R. H. ELLIS HEAT RECOVERABLE ARTICLE AND PROCESS 5 Sheets-Sheet 1 Filed Nov. 5, 1965 JVENTOR.

A7'7Uf/l/f/5 July 15, 1969 R. H. ELLIS HEAT RECOVERABLE ARTICLE AND PROCESS Filed NOV. 5, 1965 50 7A Jim 6.

3 Sheets-Sheet 2 zaaaz/z 624/6 INVENTOR.

y 1969 R. H.' ELLIS HEAT RECOVERABLE ARTICLE AND PROCESS Filed Nov. 5, 1965 3 Sheets-Sheet 5 ZGkSF/z. 546/6 INVENTOR.

W flax Arfaz/r/fks' United States Patent US. Cl. 138156 21 Claims ABSTRACT OF THE DISCLOSURE A closure sleeve for pipes or the like constructed from a piece of independently dimensionally heat unstable material, that is, material that will return to its original shape and dimensions upon application of heat alone. The member is typically fabricated in tubular form and is provided with an elongated ridge or rail extending along its length. The member and rail are then split along their length so that the sleeve can be positioned around pipe. A flexible channel or fastener is then slipped over the rail and the part recovered, the rail and fastener being dimensioned so that the split portions of the rail cannot be withdrawn from the fastener and the tubular shape of the sleeve is retained.

This invention relates to a heat recoverable article and more particularly relates to a heat shrinkable part that can be positioned around a cable, pipe, connector, or the like and then heat recovered in place.

There are many instances where it is desirable to provide a sealing, insulating or protective closure member for elongated objects such as cables, pipes, or the like where the ends of the elongated objects are not accessible, or if accessible, where it is undesirable to disconnect or otherwise displace them from their original position. In US. patent application Ser. No. 475,742, now Patent No. 3,379,218 filed on July 29, 1965 by Julian S. Conde and assigned to the assignee of the present application, there is disclosed a closure member suitable for this purpose. Im the Conde application, the disclosure of which is incorporated herein by reference, the closure member disclosed comprises an independently dimensionally heat unstable sleeve which is split along its length and which is provided with a plurality of buttons and cooperating holes by means of which the edges of the split sleeves can be joined after the sleeve is wrapped around a pipe or the like and before it is heat recovered. While this type closure member has been found to be quite satisfactory in use, some difiiculty has been experienced in adapting it for use in situations where the object to be covered is irregular in shape as is the case, for example, when assembling a wire harness including a group of wires which diverge or branch. This type closure member also requires a number of fairly time consuming fabrication steps even for straight tubing.

It is accordingly an object of the present invention to provide a closure member which is cheap, easy to install, and which can be formed to fit a large number of irregularly shaped objects.

It is another object of the present invention to provide such a closure member that can be easily removed and replaced when repair of the protected object is necessary.

It is also an object of the present invention to provide such a closure member that is easy to fabricate and quick to install.

It is another object of the present invention to provide such a continuous flexible closure member which may be used with objects of different sizes.

It is a further object of the present invention to provide a process for making such a closure member.

3,455,336 Patented July 15, 1969 These and other objects and advantages of the present invention will become more apparent upon reference to the accompanying description and drawings in which:

FIGURE 1 is a perspective view of a first embodiment of the closure member of the present invention prior to installation;

FIGURE 2 is a plan view of the closure member of FIGURE 1 after installation;

FIGURE 3 is a cross-sectional view taken along lines 3-3 of FIGURE 2;

FIGURE 4 is an enlarged detail view of a fastener according to the present invention;

FIGURE 5 is an enlarged view, partly in section, of the channel used in fastening the closure member of the present invention;

FIGURE 6 is a side elevation, partly in section, showing a second embodiment of the present invention;

FIGURE 7 is a cross-sectional view taken along lines 7-7 of FIGURE 6;

FIGURE 8 is a side elevation of a third embodiment of the present invention;

FIGURE 9 is a cross-sectional view taken along lines 9-9 of FIGURE 8;

FIGURE 10 is an enlarged detail view of a modification of the fastener of FIGURE 4;

FIGURE 11 is a cross-sectional view of tubing used in a fourth embodiment of the present invention;

FIGURE 12 is a cross-sectional view of a fourth embodiment of a closure member according to the present invention before final installation;

FIGURE 13 is a cross-sectional view of the closure member of FIGURE 12 after final installation; and

FIGURE 14 is a perspective view of a modified fastener for use in the present invention.

Briefly, the present invention, like the invention disclosed in the aforementioned Conde application, utilizes an independently dimensionally heat unstable member or part as a closure member. In general, such a part is made of a material capable of having the property of plastic or elastic memory imparted thereto which is heated to above its crystalline melting temperature and expanded under pressure to a configuration greater than its normal configuration and then cooled while kept under pressure. A part treated in this manner will retain its expanded position until it is again heated to its crystalline melting temperature at which time it will recover to its original shape. Examples of such heat recoverable materials may be found in Currie Patent 2,027,962 and Cook et al. Patent 3,086,242, the disclosures of which are incorporated herein by reference. Polymeric materials which have been cross-linked by chemical means or by irradiation, for example, with high energy electrons or nuclear radiation, are preferred for use in the present invention. Non-crystalline polymeric materials exhibiting the property of plastic or elastic memory, such as polyurethane, ionomers, etc. could also be used in practicing the present invention. Since the. closure members of the present invention can be made from material having either plastic or elastic memory, the terms elastic memory and plastic memory are used interchangeably and are intended to be mutually inclusive.

According to the present invention, such a part is molded, extruded or formed with an elongated ridge or rail extending either outwardly from its outer surface or inwardly from its inner surface. The rail extends along the entire distance that it is desired that the interior of the part be accessible and it is formed in such a manner that it can be out along its longitudinal axis to allow the separation of the part. If the part has been molded, a simulated channel slightly smaller than the one to go on the part is used to restrict expansion of the rail and insure the proper configuration of the rail after the part has been expanded and the part is then expanded under heat and pressure and then cooled while maintained under pressure; The simulated channel, if one is used, is then removed and the rail slit along its entire length. A flexible channel or fastener formed of plastic or metal is provided to cooperate with the rail to hold its two portions sothat the part is retained in the desired configuration during and after recovery. After slitting, the part can be positioned 1 around an object such as a group of wires or the like, the portions of the rail brought together, and the channel slipped over the rail. When heated to a temperature above the crystalline melting temperature of the material from which it is constructed, the part will recover toward its original shape and will firmly engage the object to be protected. As a result of this initial installation, the part assumes the' correct size of the particular application apd it can now be removed and then reinstalled without the necessity of reheating. Since the part shrinks toward its original size, it can be used with a large number of different size objects having similar configurations. If desired, the interior of the part can be provided with a fusible insert or lining, such as a sealing compound. The part can also be made so that a bond is formed between the two portions of the rail. In such a case, of course, the part cannot be removed and reinstalled.

Turning now to FIGURE 1, there is shown a first embodiment of the present invention. In this embodiment, a part or transition generally indicated as is fabricated of a material capable of having the property of plastic or elastic memory imparted thereto. The part 10 isY- shaped and has a stern portion 12 and communicating arm portions 14 and 16. A ridge or rail 18 is formed along the entire length of the arm 14 and one side of the stem 12 while a similar ridge or rail 20 is formed along the arm 16 on the other side of the stem 12. The rails are similar and, as can be seen by inspection of the rail 20, preferably have a flattened top portion 22 and a reduced or neckeddown portion 24 adjacent the surface of the part. The rails are longitudinally split along their entire length so that the interior of the arms 14 and 16 and the stem 12 are accessible. This permits the part to be positioned over a branch in any object to be protected such as, for example, a branch in a group of wires 26 shown in phantom of FIGURE 1. The rails 18 and 20 are shaped so that the volume of material in the necked-down portions is less than that in the top portion.

In order to join the two facing edges or sections of a rail, the edges are brought into abutment and a fastener or channel 30 is slid over them. The channel 30 is preferably a generally C-shaped piece of material, either metal or plastic, having a top section 32 for cooperating with the top surface of the rail and curved side portions 34 that wrap around the top portion of the rail and extend into the undercut formed by the necked-down portion 24. As can best be seen in FIGURES 4 and 5, the rail 30 is preferably provided with a plurality of notches 36 along its length so that the rail is rendered relatively flexible.

The part 10 is formed by molding the part into the desired shape, including the rails 18 and 20. The part is then heated to above the crystalline melting temperature of the material from which it is fabricated and expanded to a desired size, for example, by the application of pressure to the interior of the part. During the expansion process, a simulated channel slightly smaller than the one to go on the finished part is slid over the rails 18 and 20 to restrict their expansion. This allows the later free insertion of the actual channel over the rail on expanded parts. After expansion, the part is cooled while pressure is stillrnaintained. After cooling, the pressure can be removed and the part will remain in its expanded configuration. The rails 18 and 20 are then longitudinally split to form mating sections or edges 38 and 40. As can be seen in FIGURE 3, the rails can be split to have a vertical oifset 42 so that accurate vertical positioning of the mating sections 38 and 40 can be accomplished.

After the rails are split, the part is ready for use. Since the part is split along its entire length on both sides, it can easily he slipped over a divergence or branch, in an object to be protected, for example, in the group of wires 26 shown in phantom and the channels 30 then slid over the rails 18 and 20. If the part 10 is now heated to above the crystalline melting temperature of the material from which it is fabricated, it will recover toward its original dimensions and in so doing will tightly engage the object about which it is positioned, thereby forming a strong and long lasting protective cover or closure, The tightness of the channel in the necked-down area restricts the movement of material during the heat recovery process and insures that the two mating sections are kept together. If, at a later time, any repair or other work must be done to the protected object, the part can be removed simply by sliding the channels 30 off the rails. Once the repairs have been made, the same part or boot can now be put back in place by merely reassembling it in place and reinserting the channels. The heat shrinkable properties of the boot or part permit one boot to be used with a wide variation of object sizes. For example, in the wire group discussed, the member or size of the wires could be changed without changing the closure part. After the initial installation, the part or boot assumes the correct size for that application and reassembly does not require reheating.

In some cases, it may be necessary to have only one of the arm portions split, for example, when it is desired to make a splice to a main electrical line. In such a case, only the main line can not be out. If only one arm portion is to be split, the other is preferably not provided with a rail.

To restrict the channel from vibrating off the rail, a small raised boss 46 is preferably formed at each end of each rail. The bosses are flattened out during the expansion process, allowing the channel to slip into place. Heating causes the bosses to re-expand to their original shape and restricts the movement of the channel.

Turning now to FIGURES 6 and 7, a second embodiment of the present invention is illustrated. This embodiment is similar to the previously described embodiment with the exception that rather than being branched the part or boot shown is shaped to cover an object having a reduced diameter along a portion of its length. The part 50 consequently is provided with a region 52 of a first diameter, a region 53 of a reduced diameter, and a transition region 54 joining the regions 52 and 53. As was the case with the previous embodiment, the part 50 is molded or otherwise formed with a ridge or rail 58 similar in structure to the rails 18 and 20. The rail is split longitudinally and a channel 60 identical to the channel 30 is provided for retaining the two split sections of the rail in position. Because the channel 60 is flexible, it can easily follow the contour of the part 50 and thereby hold together the mating sections of the rail along their entire length. As shown in FIGURE 7, the separation 62 of the rail 58 is vertical and is not provided with any oifset. The part 50 is expanded and installed in the same manner as is the part 10.

FIGURES 8, 9 and 10 show another embodiment of the present invention. The part 70 shown in this figure is what is generally referred to as a boot. In this embodiment, as in the previous embodiments, the part is formed with a rail 72 which is similar to the rails previously described and which-cooperates with a channel 74 which is similar to the channels 30 and 60. In this embodiment, when the rail 72 is split longitudinally, it is provided with a plurality of serrations 76 which permits very accurate longitudinal positioning of the two mating sections. Of course, the rail 72 can be provided with a vertical offset or with no offset at all as described in connection with the previous rails while the previous rails can be provided with longitudinal serrations if desired.

Other methods of providing accurate longitudinal and vertical positioning of the mating parts will be obvious to those skilled in the art and are included within the scope of the present invention.

Turning now to FIGURES ll14, an embodiment of the present invention is illustrated which utilizes an extruded tubing having the same diameter along its entire length. As shown in FIGURE 11, a tubing 80 is extruded with a ridge or rail 82 formed along its entire length and extending inwardly from its inner surface. The tubing is then expandede and the rail split longitudinally along its entire length into two portions 84 and 86. The tubing is now inverted, or turned inside out, and the edges 88 and 90 of the tubing brought into engagement. This results in the previously matching portions 84 and 86 of the rail being directed away from each other and the formation of a generally T shaped rail, the vertical leg of the T being made up of the edges 88 and 90 of the tubing. A channel or fastener 92 can now be slid over the rail to hold it in place around, for example, a cable 94.

As best shown in FIGURE 14, the channel 92 is a modification of the channels shown in FIGURES 1 through 10. Flexibility is imparted to the channel 92 by forming slits 96 in the upper and side surfaces of the channel. Longitudinal connection is provided by leaving areas 98 that run along the entire length of the inner ends of the curved side surfaces of the channel. Of course, either type of channel can be used in any of the modifications shown.

After the channel is slipped over the rail, the tubing or part can be heated to above the recovery temperature of the material from which it is fabricated. This heating will cause the part to recover toward its original dimensions with the result that the cable 94 will be tightly engaged. If desired, the interior surface of the tubing, as applied (the exterior as extruded), may be coated with a suitable heat activated adhesive so that a tight seal is obtained. Any other liner material that would not prevent the desired recovery of the part could also be used in this part, as well as in the parts of the other illustrated embodiments.

As the tubing shrinks o-r recovers toward its original diameter, the edges 88 and 90 of the tubing will tend to pull out of the channel 92. However, this motion will be stopped, and further movement prevented, by the rail portions 84 and 86 firmly engaging the curved side surfaces of the channel 92. In addition, as the tubing recovers, its walls will become thicker with the result that the edges 88 and 90 will expand to tightly engage the areas 93 of the channel. The tubing will thus be prevented from freeing itself from the channel.

If desired, the various parts shown and described above can be fabricated so that the two portions joined by the channel will bond together when the part is recovered. This can conveniently be done, for example, by only slightly cross-linking these two portions, so that these portions will be heat sealable at the recovery temperature. Parts of this nature, of course, cannot be removed and reinstalled, their installation being permanent. This object could also be obtained by fabricating the rails separately from the remainder of the part, from the same or different material, and then heat bonding the rail to the remainder of the part after the remainder has been crosslinked. Such a joinder of two or more separate elements, of the same or different material, to make one integral part could also be done, of course, to fabricate a nonbonding or removable part of the types illustrated. The only requirement for such a fabrication is that the materials used be compatible bonding materials.

While the shape of the rails illustrated and described is one generally having a flat top portion and rounded side portions leading into the necked-down portion, it will be obvious to those skilled in the art that the top portion of the rail can have any desired cross-section so long as it has a lateral dimension sufficiently larger than the lateral dimension of the necked-down portion to provide a secure connection or engagement with the channel. If necessary, the channel can be formed to match the particular rail configuration.

From the foregoing description, it can be seen that a novel and relatively easily fabricated closure or protective part has been provided which can be used with regularly or irregularly shaped objects and which permits the part to be easily installed and easily removed and reinstalled from the protected object. Furthermore, any individual part can be used with objects having the same general configuration but having a wide variation in size. While several specific embodiments of the invention are illustrated and described, it is obvious that many other shapes and configurations are possible according to the teachings of the present invention and consequently these embodiments are illustrative only, the scope of the invention being measured by the appended claims.

I claim:

1. A heat recoverable closure member comprising an elongated independently dimensionally heat unstable tubular member, an integral protuberance on the outer surface of said member and having a narrow portion adjacent said surface and a wide portion remote therefrom, said protuberance being longitudinally split along its entire length, and fastening means for retaining the split sides of said protuberance in abutting relationship during heat recovery of said member, said fastening means comprising a strip of material having a top surface for overlying the wide portion of said protuberance and curved side surfaces for extending around and under said wide portion of said protuberance.

2. A heat recoverable closure member comprising an elongated tubular member of material having the property of elastic memory, an integral ridge on the outer surface of said member and extending along the length thereof, said ridge having a necked-down portion adjacent said surface and a wide portion remote therefrom, said ridge being longitudinally split along its entire length into two mating portions, and fastening means for sliding over said ridge and retaining said mating portions in abutting relationship during heat recovery of said member, said fastening means comprising a strip of flexible material having a top surface for overlying the wide portion of said ridge and curved side surfaces for extending around and under said wide portion of said ridge, the inner ends of said surfaces being separated by a distance greater than the thickness of said necked-down portion of said ridge.

3. The closure member of claim 2 wherein the volume of material in the necked down portion of said ridge is less than the volume of material in the wide portion of said ridge.

4. The closure member of claim 2 wherein said mating portions of said split ridge are provided with a vertical offset.

5. The closure member of claim 2 wherein said mating portions of said split ridge are provided with longitudinal serrations.

6. The closure member of claim 2 wherein said mating portions of said split ridge comprise portions of the inner surface of said member.

7. The closure member of claim 2 wherein said fastening means comprises a generally C-shaped strip of material having a plurality of notches formed therein along the length thereof to render said strip flexible.

8. The closure member of claim 7 wherein said strip is metal.

9. The closure member of claim 2 wherein said tubular member is of varying diameter along its length.

10. The closure member of claim 2 wherein said tubular member is curved whereby one end thereof is displaced approximately from the other end thereof.

11. A heat recoverable closure member comprising an elongated Y-shaped tubular member having a stern and a pair of arms extending therefrom, said tubular member being fabricated of a material having the property of elastic memory, a first integral ridge formed on the outer surface of said member and extending along the length of one arm and along one side of said stem, a second integral ridge formed on the outer surface of said member and extending along the length of the other arm and the other side of said stem, each of said ridges having a necked-down portion adjacent the surface of said member and a wide portion remote therefrom and being longitudinally split into two mating portions, and first and second fastening means for sliding over said first and sec ond ridges respectively and retaining the mating portions thereof in abutting relationship during heat recovery of said member, each of said fastening means comprising a strip of flexible material having a top surface for overlying said wide portion and curving side surfaces'for extending around and under said wide portion, the inner ends of said side surfaces being separated by a distance greater than the thickness of the necked-down portion of said ridge.

12. A closure member comprising an elongated tubular member, the wall thereof comprising a material which has been dimensionally changed from an original heat stable form to an independently dimensionally heat unstable form capable of moving in the direction of its original form upon the application of heat alone, an integral rail formed on the outer surface of said wall and extending along the length thereof, said rail having a necked-down portion adjacent said wall and a wide portion remote therefrom, said rail being longitudinally split along its entire length into two mating portions, and fastening means for sliding over said rail and retaining said mating portions in abutting relationship when said member is heated to the recovery temperature of said material, said fastening means comprising a strip of material having a top surface for overlying the wide portion of said rail and curved side surfaces for extending around and under said wide portion of said rail, the inner ends of said side surfaces being separated by a distance greater than the thickness of said necked-down portion of said rail.

13. The closure member of claim 12 wherein the volume of material in the necked-down portion of said rail is less than the volume of material in the wide portion of the rail.

14. The closure member of claim 12 wherein said fastening means comprises a generally C-shaped strip of material having a plurality of notches formed therein along the length thereof to render said strip flexible.

15. The closure member of claim 12. wherein said mating portions of said split rail comprise portions of the inner surface of said member.

16. A heat recoverable closure member comprising a piece of material having the property of elastic memory, a first integral protuberance formed on the surface of said material adjacent one edge thereof, a second integral protuberance formed on the surface of said material adjacent an opposite edge thereof, fastening means comprising a strip of flexible material having a top surface and curved side surfaces, the surfaces of said piece of material adjacent said edges being brought into abutting relationship with said protuberances extending outwardly therefrom and said fastening means being positioned around said protuberances, said protuberances cooperating with said fastening means to hold said surfaces in abutting relationship whereby a tubular member is formed from said piece of material, said fastening being capable of maintaining said surfaces in abutting relationship during heat recovery of said member.

17. A closure member comprising an elongated tubular member of a material which has been dimensionally changed from an original heat stable form to an independently dimensionally heat unstable form capable of tudinal separation extending its entire length, a first integral protuberance formed on the outer surface of said member on one side of said separation, a second integral protuberance formed on the outer surface of said member on the other side of said separation, and fastening means for sliding over said protuberances and retaining the inner surfaces of said member adjacent said separation in abutting relationship, said fastening means comprising a strip of material having a top surface for overlying the edges of said member at said separation and curved side surfaces for extending around said protuberances and preventing removal of said protuberances from said fastening means as a result of a heat induced dimensional change.

18. The closure member of claim 17 wherein said fastening means comprises a generally C-shaped strip of material having a plurality of notches formed therein along the length thereof to render said strip flexible.

19. A heat recoverable closure member adapted to be heat recovered onto an object having a larger dimension in the direction of recovery than said member after recovery, comprising: a piece of material that has been dimensionally changed from an original heat stable form to an independently dimensionally heat unstable form capable of moving in the direction of its original form upon the application of heat alone, said piece having first and second edge portions, said first edge portion having a first elongated integral protuberance extending outwardly therefrom, said first protuberance having a neckeddown portion adjacent to said edge portion and a Wide portion remote therefrom, said second edge portion having a second elongated integral protuberance extending outwardly therefrom, said second protuberance having a necked-down portion adjacent to said edge portion and a wide portion remote therefrom, said necked-down portions of said protuberances being brought into abutting relationship to form said piece of material into a tubular member, and fastening means for positioning over said protuberances, said fastening means being capable of maintaining said protuberances in abutting relationship during heat recovery of said piece of material around said object.

20. The closure member of claim 19 wherein said fastening means comprises a C-shaped strip of flexible material having a top surface for overlying said wide portions of said protuberances and curved side surfaces for extending around said wide portions and into said necked-down portions of said protuberances.

21. The closure member of claim 19 wherein the volume of material in the necked-down portions of said protuberances is less than the volume of material in the wide portions of said protuberances.

References Cited UNITED STATES PATENTS 1,645,748 10/1927 Garnrneter 138-152 2,756,172 7/1956 Kidd 138-149 3,233,699 2/1966 Plummet 138-149 817,314 4/1906 Hahn 138-158 XR 822,004 5/1906 Kronauer 138-158 2,027,962 1/1936 Currie 18-55 2,650,180 8/1953 Walker 138-158 XR 2,714,424 8/ 1955 Atkinson 138-158 XR 3,070,274 12/1962 Elam 138-156 XR 3,086,242 4/1963 Cook et al. 18-1 FOREIGN PATENTS 570,256 2/ 1959 Canada.

LAVERNE D. GEIGER, Primary Examiner H. K. ARTIS, Assistant Examiner U.S. Cl. X.R. 138-99, 158 

